Formation of diaryl(allyl)phosphine in π -allyl palladium(II) induced cleavage of triarylphosphines

A reverse migration of allylic group from palladium to phosphorus and the formation of diaryl(allyl)phosphine in the π -allyl palladium(II) induced cleavage of triarylphosphines has been demonstrated.     

Synthesis of diaryl thioethers from aryl halides and potassium thiocyanate

An efficient palladium catalyst was synthesized using nicotine, benzyl chloride and palladium chloride. The structure of this catalyst was characterized and it was then used for the synthesis of diaryl sufides. A variety of diaryl thioethers were synthesized under relatively mild reaction conditions. This protocol avoids foul‐smelling thiols via cross‐coupling of aryl halides with potassium thiocyanate and all substrates give the corresponding products in good to excellent yields in the presence of low amounts of the catalyst. Copyright © 2014 John Wiley & Sons, Ltd.     

Palladium-Catalyzed Carbonylative Lactonization of Propargyl Alcohols with Organic Dichalcogenides and Carbon Monoxide

The reaction of propargylic alcohols with diaryl disulfides and carbon monoxide in the presence of tetrakis(triphenylphosphine)palladium leads to a novel thiolative lactonization to afford beta-(arylthio)-alpha,beta-unsaturated lactones in moderate to good yields. Similar conditions can be employed with homopropargylic alcohols, giving the corresponding delta-lactones with a beta-arylthio group successfully. The reaction using diaryl diselenides in lieu of diaryl disulfides also attains a similar one-pot thiolation/lactonization sequence to provide the corresponding beta-selenobutenolides (7).     

Hindered diarylether and diarylsulfone bisphosphine ligands: atropisomerism and palladium complexes

Phosphines and bisphosphines derived from hindered ortho-substituted diaryl ethers and diarylsulfones by lithiation are, with appropriate substitution patterns, resolvable atropisomeric ligands which form crystalline complexes with palladium dichloride.     

Supported Palladium-Catalyzed Carbonylative Synthesis of Diaryl Ketones from Aryl Bromides and Arylboronic Acids

A palladium supported on graphitic carbon nitride (Pd/g-C₃N₄) catalyzed carbonylative reaction of aryl bromides and arylboronic acids by has been developed for the construction of diaryl ketones. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source, the reaction proceeded well to give various diaryl ketones in moderate to good yields.     

Synthesis of dictyomedins using phosphazene base catalyzed diaryl ether formation

Dictyomedins isolated from dictyostelium cellular slime molds were synthesized by using diaryl ether derivatives as key intermediates for the cyclization to dibenzofuran followed by palladium catalyzed intramolecular biaryl formation.     

Palladium-catalyzed dehydroarylation of triarylmethanols and their coupling with unsaturated compounds accompanied by C-C bond cleavage

Triarylmethanols are effectively dehydroarylated and reacted with some unsaturated compounds by using an appropriate palladium catalyst system such as Pd(OAc)2-P(1-Nap)3 (1-Nap = 1-naphthyl) to give the corresponding arenes and hydroarylation products, respectively, along with diaryl ketones.     

Thioketone‐Directed Palladium(II)‐Catalyzed C−H Arylation of Ferrocenes with Aryl Boronic Acids

A palladium(II)‐catalyzed thioketone‐chelation‐assisted direct C?H arylation of ferrocenes is described. With thioketone as an efficient directing group, various monoaryl‐ and diaryl‐substituted thiocarbonylferrocenes were obtained by palladium‐catalyzed direct C?H functionalization in high yields under mild and base‐free reaction conditions. Furthermore, the arylated thiocarbonylferrocene could undergo diverse transformations.     

HYPERVALENT IODINE IN SYNTHESIS. 83. PALLADIUM-CATALYZED CARBONYLATIVE COUPLING OF DIARYLIODONIUM SALTS MEDIATED BY INDIUM

ABSTRACT

In the presence of palladium catalyst and indium diaryliodonium salt; react with carbon monoxide under mild reaction conditions to give diaryl ketone; in moderate yields.     

Stereoselective Cross-Coupling of Baylis–Hillman Acetates with Diphenyl Disulfides and Diselenides Using Palladium Acetate

An efficient method is described for the stereoselective synthesis of diorganyl chalcogenides from a variety of Baylis–Hillman acetates and diaryl chalcogens using palladium catalyst. This reaction is a convenient new method to produce unsymmetrical sulfides and selenides in good yields.     

2‐Pyridylquinoxaline derivatives as N,N‐ligands for palladium‐catalyzed Suzuki–Miyaura reaction

The Suzuki–Miyaura reaction of aryl bromides with benzeneboronic acid catalyzed by bis(chloro)(2‐pyridylquinoxaline)palladium(II) was investigated. The scope of the bis(chloro)(2‐pyridylquinoxaline)palladium(II) was determined in toluene at 80 °C using KOH as base. Using a 0.1% molar ratio of bis(chloro)(2‐pyridylquinoxaline)palladium(II) C1 as a catalyst, aryl bromides reacted with benzeneboronic acid to afford diaryl derivatives in excellent yield. Copyright © 2009 John Wiley & Sons, Ltd.     

One-pot synthesis of symmetrical and unsymmetrical aryl sulfides by Pd-catalyzed couplings of aryl halides and thioacetates

Aryl sulfides were obtained from the coupling reaction of S-aryl (or S-alkyl) thioacetates and aryl bromides in the presence of palladium catalyst. This reaction method enables the one-pot synthesis of symmetrical and unsymmetrical diaryl sulfides by employing potassium thioacetate with aryl iodides and aryl bromides.     

One-pot synthesis of diarylalkynes using palladium-catalyzed sonogashira reaction and decarboxylative coupling of sp carbon and sp2 carbon

Decarboxylative coupling of sp-sp2 carbons is possible by palladium catalyst. Employing propiolic acid (1) as a difunctional alkyne, and using the consecutive reactions of the Sonogashira reaction and the decarboxylative coupling, unsymmetrically substituted diaryl alkynes were obtained in moderate to good yield.     

Hydroxylamine O-benzyl ether as an ammonia equivalent in the catalytic amination of aryl halides

The palladium catalysed amination of aryl bromides with hydroxylamine O-benzyl ether leads to the formation of diaryl or triarylamines depending on the size of the aryl bromide, the number of equivalents used or the conditions employed.     

Diaryl Sulfoxides from Aryl Benzyl Sulfoxides: A Single Palladium‐Catalyzed Triple Relay Process

A novel approach to produce diaryl sulfoxides from aryl benzyl sulfoxides is reported. Optimization of the reaction conditions was performed using high‐throughput experimentation techniques. The [Pd(dba)₂]/NiXantPhos catalyst system successfully promotes a triple relay process involving sulfoxide α‐arylation, C? S bond cleavage, and C? S bond formation. The byproduct benzophenone is formed by an additional palladium‐catalyzed process. It is noteworthy that palladium‐catalyzed benzylative C? S bond cleavage of sulfoxides is unprecedented. A wide range of aryl benzyl sulfoxides, as well as alkyl benzyl sulfoxides with various (hetero)aryl bromides were employed in the triple relay process in good to excellent yields (85–99 %). Moreover, aryl methyl sulfoxides, dibenzyl sulfoxides, and dimethylsulfoxide could be utilized to generate diaryl sulfoxides involving multiple catalytic cycles by a single catalyst.     

Pd-NHC-catalyzed synthesis of diaryl ketones

With N-hetereocyclic carbene and palladium catalysis, diaryl ketones with a variety of functional groups that span from electron withdrawing to electron donating substitutions can be conveniently synthesized using the corresponding aryl boronic acid and N-acyloxyphthalimide.     

A new pathway for the preparation of diaryl acetylenes

A simple method for the preparation of diaryl acetylenes in yields up to 61% from aryl bromides and 1-bromo-2-chloroethane using the palladium catalyst (dppb)Pd(OAc)₂ under PTC conditions (solid KOH/18-crown-6) has been developed.     

Palladium‐Catalyzed Regiodivergent Substitution of Propargylic Carbonates

The palladium(0)‐catalyzed, ligand‐controlled, regioselective addition of diaryl acetonitrile pronucleophiles to propargylic carbonates is reported. Selective formation of either terminal 1,3‐dienyl or propargylated products is proposed to arise from a change in reaction mechanism controlled by the denticity of the coordinating ligand.     

Synergistic N‐Heterocyclic Carbene/Palladium‐Catalyzed Umpolung 1,4‐Addition of Aryl Iodides to Enals

An umpolung 1,4‐addition of aryl iodides to enals promoted by cooperative (terpy)Pd/NHC catalysis was developed that generates various bioactive β,β‐diaryl propanoate derivatives. This system is not only the first reported palladium‐catalyzed arylation of NHC‐bound homoenolates but also expands the scope of NHC‐induced umpolung transformations. A diverse array of functional groups such as esters, nitriles, alcohols, and heterocycles are tolerated under the mild conditions. This method also circumvents the use of moisture‐sensitive organometallic reagents.     

Palladium‐Catalyzed Suzuki–Miyaura Cross‐Coupling of Secondary α‐(Trifluoromethyl)benzyl Tosylates

A palladium‐catalyzed C(sp³)−C(sp²) Suzuki–Miyaura cross‐coupling of aryl boronic acids and α‐(trifluoromethyl)benzyl tosylates is reported. A readily available, air‐stable palladium catalyst was employed to access a wide range of functionalized 1,1‐diaryl‐2,2,2‐trifluoroethanes. Enantioenriched α‐(trifluoromethyl)benzyl tosylates were found to undergo cross‐coupling to give the corresponding enantioenriched cross‐coupled products with an overall inversion in configuration. The crucial role of the CF₃ group in promoting this transformation is demonstrated by comparison with non‐fluorinated derivatives.